HOUSTON -- Felix Hernandez continued his recent string of strong outings with another dominant performance Sunday.
Hernandez threw six shutout innings, scattering four hits and striking out seven as the Seattle Mariners beat the Houston Astros 12-5 to complete a three-game sweep. The Mariners earned their sixth win in a row.
Hernandez (11-4) has not allowed a run in his last two starts, spanning 14 innings, and he has won sixth straight.
The last time Hernandez had a 7-0 lead, as he did after Seattle scored seven times in the top of the second Sunday, he gave up seven runs over three innings against the Angels.
"He's one of those guys, it might happen once, but it's not going to happen again," Mariners manager Eric Wedge said. "I thought he did a good job against them. They made him work, but he did a good job and made pitches."
Hernandez has not allowed a run in two starts against the Astros this season, giving up just nine hits and striking out 16 over 12 innings. He lowered his league-leading ERA to 2.43.
Hernandez said everything was working Sunday.
"Breaking ball was there, changeup was there, had control of my fastball, so it was fun today," Hernandez said. "I feel pretty good. I've just been throwing a lot of strikes, trying to control the walks and just pound the strike zone, and that helped me a lot."
Nick Franklin had two hits, including a grand slam, while Dustin Ackley tied a season high with three hits for the Mariners, who swept their second straight series for the first time since sweeping the Minnesota Twins and Cleveland Indians from Aug. 17-22, 2012.
"It was definitely a great bounce-back from yesterday and only having the one hit," Franklin said, referring to Seattle's unusual 4-2 win Saturday in which the Mariners were nearly no-hit. "But at the same time, we've been swinging it well, and it was just one of those adjustment periods we had to go through and get back after it the next day."
Houston lost its fifth in a row and eighth in the last nine games to fall to a major-league-worst 33-64. Jose Altuve and Jake Elmore each had two hits for the Astros.
Franklin capped off the seven-run second inning with his first career grand slam to give the Mariners (46-52) a 7-0 lead.
Kendrys Morales started the inning with a single before Kyle Seager reached on an error by Elmore, Houston's shortstop. After Jordan Lyles struck out Justin Smoak, Michael Saunders walked to load the bases.
Ackley scored on a single, and Henry Blanco plated one more after getting hit by the first pitch he saw. Brad Miller singled to left to up the lead to 3-0 before Franklin's homer.
Houston manager Bo Porter said the inning snowballed after Elmore's error.
"You look at the seven-run second inning, and you have a double play that is not made, not turned, and instead of it being two outs with nobody on base, it is first and second with nobody out," Porter said. "I have said this time and time again, you have to make the plays that should be made to win games at this level."
Seattle tacked on three more in the fifth. Raul Ibanez led off the inning with a double and scored on a Morales single. After Lyles hit Seager with a pitch, Smoak singled to chase the right-hander, who exited with the bases loaded.
Lucas Harrell induced Saunders to ground into a fielder's choice, plating Morales to extend the lead to 9-0 before Ackley's sacrifice fly extended Seattle's advantage to 10-0.
Miller upped the lead to 11-0 with a run-scoring single in the seventh before Houston got on the board with an RBI single by Altuve in the bottom half of the inning off Hector Noesi.
Saunders made it 12-1 with a run-scoring double in the eighth, and the Astros scored four in the ninth.
Lyles (4-4) gave up a career-high 10 runs -- nine earned -- on eight hits with two walks and three strikeouts in four-plus innings. His previous career high for runs allowed was nine against Milwaukee on Aug. 1, 2012.
Lyles said he was missing around the zone and was just a bit off.
"It really came down to fastball command," Lyles said. "Unfortunately, every batter was ahead, and I was having to come to them. I walked a couple guys, hit a guy. The balls that were put in play were hit pretty hard, and that was simply because I fell behind so many guys."
NOTES: Even though the Mariners saw their franchise-record 23-game home run streak snapped Saturday night, Seattle entered the day third in the majors with 119 homers this season. ... A day after Astros LHP Erik Bedard took himself out of a no-hit bid after 6 1/3 innings, Porter said he was not going to let Bedard, who was at 109 pitches, go past 120 pitches. ... Saunders extended his hitting streak to 10 games with a double in the eighth. ... After the game, the Astros designated SS Ronny Cedana and 1B Carlos Pena for assignment and recalled SS Jonathan Villar from Triple-A Oklahoma City.